Stencil construction



1966 R. MOONEY ETAL 3,280,732

STENCIL CONSTRUCTION Filed Dec. 6, 1960 """WHIIIIIII II! M I 1 VI /3INVENTORS LA UEENCE .P. Mooms BY LA 022m? 3 Law:

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ATTOEWE'V United States Patent 3,280,732 STENCIL CONSTRUCTION LaurenceR. Mooney and Laurence B. Lueck, St. Paul,

Minn., assignors, by mesne assignments, to Elliott Business Machines,Inc., Randolph, Mass., a corporation of Massachusetts Filed Dec. 6,1960, Ser. No. 75,073 1 Claim. (Cl. 101-1282) The present invention isconcerned generally with an improved stencil assembly, and moreparticularly to an improved stencil assembly which includes, incomposite, a master marking sheet, a sheet having a sensitive markingfilm, and adhesive means for applying the composite arrangement to aworking surface.

In stencil work generally, particularly in stencil work wherein aplurality of individual stencil assemblies are stacked in a storagecontainer, normal usage requires that the sheets be uniformly orientedwithin the container as well as being free one from another. It has beena practice to employ separating sheets which may be utilized betweenindividual stencil assemblies packed together in a single cartonenclosure. These separating sheets must be separated out prior to use.For example, in a stencil assembly which is particularly adapted for usein a situation wherein a shipping label, invoices, as well as otherbilling material may be prepared from a single master stencil, it isdesirable to utilize a stencil master which has means for lightlyattaching the assembly onto a working surface. In this connection, apressure sensitive film is deemed most desirable in order to hold thestencil in position while it is being utilized. Of course, the use of apressure sensitive film on the stencil master makes it extremelydifficult to stack the individual items uniformly in a container withoutemploying a separating sheet interposed between individual stencilsheets. In accordance with the present invention, a certain film isapplied to .the top or front surface of the stencil which renders thatparticular surface nonadherent to the pressure sensitive adhesive film.This film and the pressure sensitive adhesive film are mutuallyincompatible in that they will not adhere, not one to another. Inaccordance with this feature, it is possible to place the individualstencil assemblies in superimposed stacked relationship without dangerof causing these assemblies to adhere, one to another. Inasmuch asvarious office equipment which is in use today requires that the stencilassemblies be disposed in superimposed stacked relationship, theimproved composite assembly of the present invention is particularlyadaptable for use in connection with this modern equipment. Since, nomean or spacing sheet is required, the improved stencil assemblies maybe placed into the various equipment Without need for pretreatment,removal or separation of a spacing sheet for between individual units.

It is therefore an object of the present invention to prepare compositestencil asemblies which include as a component thereof, a pressuresensitive adhesive film arranged along a first surface portion togetherwith a sec ond film adjacent a second surface portion thereof, the filmsbeing arranged in oppositely disposed superimposed relationship alongthe composite stencil assembly, and being mutually incompatible, one toanother.

It is a further object of the present invention to provide an improvedstencil composite assembly which includes a pressure sensitive filmadjacent a surface portion thereof, the immediate oppositely disposedsurface portion of said assembly being treated so as to have a filmtherealong which holds no afiinity for the pressure sensitive film,thereby permitting the materials to be maintained in superimposedstacked relationship over extended periods of time.

ICC

Other and further objects of the present invention will become apparentto those skilled in the art upon a study of the fol-lowingspecification, appended claim and accompanying drawings wherein:

FIG. 1 is a top plan view of the improved composite stencil assembly inthe present invention;

FIG. 2 is a vertical sectional view taken along the line and in thedirection of the arrows 2--2 of FIG. 1 and showing the arrangement ofthe various materials and sensitive films, the master stencil member andthe copy sheet being shown in reduced scale; and,

FIG. 3 is a vertical sectional view of a composite assembly which isprepared in somewhat modified form from the apparatus shown in FIGS. 1and 2.

In accordance with the preferred modification of the present inventionas illustrated in FIGS. 1 and 2, the stencil assembly generallydesignated 10 includes a stencil master sheet 11 and a duplicating sheetor carbon sheet 11a superimposed therewith. A backing layer 12 has anadhesive layer 13 on one surface thereof, together with a second layer14 on the other surface thereof which is provided as a specificrepellent for the pressure sensitive film 13. In this connection, thelayer 12 is entirely impervious to migration of the sensitive filmstherethrough, and may, therefore, comprise for example a backing film ofpolyvinylchloride or the like. The pressure sensitive film 13 maypreferably comprise a pressure sensitive adhesive film such as anacrylic copolymer such as ethyl acrylate-methyl methacrylate copolymer,which is heavily loaded with alkaline earth stearates, such as calciumstearate. This film has the characteristic of having an immediatewet-grab, and having a degree of adhesion which does not increase withtime. Accordingly, the stencil sheet assembly may be attached andremoved with ease, the adhesive film being releasably secured to anadjacent layer or film onto which the adhesive has been holding thecomposite label assembly. The layer 14 is likewise preferably selectedfrom the group of materials known as polymeric alkyl siloxanes.Accordingly, these composite stencil assemblies may be packaged insuperimposed relationship without requiring a separating or spacinglayer to be interposed between individual elements.

According to a modified embodiment of the present invention as shown inFIGS. 1 and 3, the stencil assembly 10 includes, in composite, a masterstencil sheet 11 and a tracing or copy sheet 11a. Copy sheet 11a isagain conventional, is impregnated with a material such as carbon or thelike for making a permanent impression or indicia on the surface of thesheet to which the stencil assembly has been initially tabbed. It may bepointed out at this time that the present invention is an improvementover the stencil assembly disclosed and claimed in US. Pat. No.2,771,026, Laurence R. Mooney, which patent is assigned to the sameassignee as the present invention. The master stencil sheet adjacent thecopy sheet is treated as is conventional, in the art, this being ahighly porous paper base which has been plastic coated so as to allowthe body of the coating to separate upon being pressed or struck with arelatively sharp object, such as an indicia producing object. The copysheet may be carbon paper, Kozutint lace type tissue having a carboncoating or the like, the copy paper likewise being conventionally usedin the art. Both the stencil master paper and the copy paper arecommercially available.

A member 22 having an adhesive film 27 along one surface is placed insuperimposed relationship over the main or master stencil sheet 11 andthe copy sheet 11a in order to retain the pair in properly arrangedsuperimposed composite relationship, one to the other and to hold theassembly in working contact with a surface to be treated.

' crease with time.

The backing paper 24 is attached or secured to the backing film 26through the pressure sensitive adhesive layer 25, this layer beingpreferably an acrylic copolymer such as ethyl acrylate-methylmethacrylate. Such pressure sensitive adhesive materials arecommercially available and widely employed in the adhesive art today.Layer 23 is a silicone film arranged along the surface of the backing24. The backing film 26 which may be, for example, a polyvinyl-chloridefilm is provided with a second adhesive layer 27 which is likewisepressure sensitive and which is provided to retain the stencil member 11and a copy member 11a in mutually predetermined relationship, andfurther to provide an adhesive area or surface which is available tohold the composite assembly on a surface such as a carton surface, aninvoice label surface or the like. The backing material 26, asindicated, comprises polyvinyl-chloride, but may also be comprised ofany material which is impervious to migration of the adhesive layers 25and 27 thereacross, these layers being, in certain instances, ofdifferent characteristics. Accordingly, thecomposite assembly of thepresent invention does not significantly age during storage and theshelf life is therefore reasonably long. Adhesive layer 27 is one whichhas an immediate wet-grab and one which has a degree of adhesion whichdoes not in- It is therefore possible to apply, remove and reapply thesestencil assemblies to a plurality of different work surfaces. Such anadhesive may be an acrylic copolymer such as ethyl acrylate-methylmethacrylate coploymer (55-45 EAMM) having a molecular weight which isrelatively low for acrylic adhesives and which has been heavily dopedwith an alkaline-earth stearate;

In accordance with the embodiments of the present invention, thecomposite stencil assemblies may be arranged in superimposedrelationship and packed in a conventional fashion without danger ofadherence between the individual assemblies or units. The siliconelayers 14 and 23 respectively are substantially noncompatible with thepressure sensitive adhesive layers 13 and 27 respectively, andaccordingly there is no tendency for the individual assemblies to stick,one to the other. This makes it possible to superimpose the assembliesin stacked relationship for use in accordance with the requirements ofmodern duplicating equipment, without requiring the operator to remove aspacing or separating layer between individual assemblies.

A suitable silicone material for use in connection with the presentinvention has been found to be a certain alkyl polysiloxane sold byDow-Corning Co., Midland,

Michigan, and identified by their code-name DC. No. 23. A secondsuitable material is their similar siloxane identified by the code-nameDC. 22 both of which are believed'to be predominantly 'di-methylsiloxanes.

For purposes of convenience of fabrication, layer 25 has been disclosedas being pressure sensitive. It will be appreciated, however, that othertypes of adhesives 4 may be satisfactorily utilized in place of thepressure sen sitive type, such as either heat activated or solvent activated adhesives.

It will be appreciated that the specific examples give] herein areprovided for purposes of illustration only an are not to be construed asa limitation upon the scope 0 coverage to which this invention isreasonably entitled What is claimed is:

In a stencil assembly comprising a relatively narrov securing striphaving a pressure-sensitive adhesive coat ing of a type to permit thesame to be removably adhere'c to another sheet, a stencil sheet afiixedon one side along one marginal edge portion to only a portion of saitadhesively coated strip, disposed in juxtaposition to the other side ofsaid stencil sheet a separate carbon shee afiixed along one marginaledge portion to only a par of the remaining exposed adhesive coating onthe bottorr side of said strip to leave a portion of the underlyingadhesive coating expose-d for removable attachment tc a selected part ofa larger sheet, the improvement wherein said securing strip consists ofa backing paper coated on one side with an alkyl polysiloxane which issubstantially mutually incompatible with said adhesive coating the otherside of said backing'paper being fixedly secured by a copolymer ofethylacrylate and methyl methacrylate to one side of a backing film ofpolyvinyl chloride, and the other side of said backing film being coatedwith the pressure-sensitive adhesive having an intermediate wetgrab,said adhesive being a relatively low molecular weight copolymer ofethylacrylate and methyl methacrylate which is heavily doped with analkaline earth stearate.

References Cited by the Examiner UNITED STATES PATENTS 1,954,805 4/1934Drew 101127 2,439,481 4/1948 Martin 1l7-68.5 2,484,416 10/1949 Martin11768.5 2,496,349 2/1950 Kellgren et al. 117-122 2,525,864 10/1950Carter 117-122 2,532,011 11/ 1950 Dahlquist et a1. 117122 2,544,3153/1951 Heldmann 117-122 2,588,367 3/1952 Dennett 1l7122 2,599,576 6/1952Morris et al 117-68.5 2,771,026 ll/l956 Mooney 101128.2 2,803,613 8/1957Kather et a1. 117-122 2,822,290 2/ 1958 Webber 117122 2,956,904 10/ 1960Hendricks 117122 2,971,863 2/1961 Kindseth et al. 11768.5 3,050,4118/1962 Keil ll768.5 3,050,425 8/1962 Carr et al 156-332 X DAVID KLEIN,Primary Examiner.

R. LEIGHEY, ROBERT E. PULFREY, Examiners.

E. T. WRIGHT, Assistant Examiner.

